On Tue, Jun 2 at 12:46, Bob Friesenhahn wrote:
On Tue, 2 Jun 2009, Roman Naumenko wrote:
Does it make sense to go with motherboards that support 32G of memory?
Can it improves zfs performance to a significant degree?
The improvement depends on how heavily the server is accessed and the
total amount of data which is accessed frequently. With sufficient RAM,
the disks will only be accessed for writes and writes will also be faster
if the data being updated is cached. If you need performance and can
afford it, then go for the 32GB of RAM.
The RAM will be the best performer, but for the cost and power, it
might be a better choice to stick with 8-16GB RAM and add an SSD or
two as a cache device.
Each 4GB FB-DIMM for that motherboard will run you about $100, so a
32GB cache SSD has about the same cost up front as 16GB of RAM. Each
FB-DIMM burns about 10W of power, compared to 2.5W for the entire SSD
when active, and virtually zero when not being accessed.
A single cache SSD should be able to easily saturate gigabit ethernet
even in random workloads if that is your performance bottleneck.
--
Eric D. Mudama
edmud...@mail.bounceswoosh.org
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